Micrometer attachment



June 11, l 4fi, MAR'HNEQ 2,401,951

MICROMETER ATTACHMENT I Filed Jan. 1, 1945 INVENTOR.

I awfw Patented June 11, 1946 UNITED STATES PATENT OFFICE MICROMETER ATTACHMENT Emil J. Martinec, Chicago, Ill.

Application January 1, 1945, Serial No. 570,819

3 Claims. 1

This invention relates to certain novel improvements in micrometer attachments.

More particularly the invention has reference to a thread gauge adapted for use with a micrometer of standard construction and without any change or alteration in the micrometer, and has for its principal object the provision of an improved construction of this character which will be highly efiicient in use and economical in manufacture.

An object of the invention is to provide a micrometer attachment by means of which the diameter of threads of different pitch may be measured and their accuracy determined.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawing showing the preferred form of construction, and in which:

Fig. 1 is a side elevational View of a micrometer showing the invention associated therewith;

Fig. 2 is a perspective view of a base member embodied in the invention;

Fig. 3 is a, perspective view of a head member embodied in the invention.

The drawings illustrate the preferred form of construction by which the several objects of the invention are accomplished. In this connection, I indicates a micrometer of a standard construction comprising a frame 2 having the spaced arms 3 and 4. The arm 4 carries the usual anvil 5, whereas the arm 3 rotatably supports the standard spindle B. To this anvil and spindle 6 is adapted to be detachably connected the thread gauge embodying this invention. In this connection the thread gauge is indicated generally at l and comprises a base 8 and a cap 9. The base 8 provides an open sleeve I which is adapted to receive the anvil 5. This base 8 provides on opposite sides of the sleeve I0, lateral arms ll having formed therein a plurality of threads I2. The cap 9 comprises a plate [3 having a central Opening I4 formed therein for the passage of the outer end portion of the spindle 6. Mounted on this spindle 6 is a collar 15, the mounting being accomplished by a set screw l'l. Outwardly from this collar 15 is a collar l8 likewise mounted on the spindle through the medium of a set screw I9. Between these collars l and 18 the plate l3 of the head 9 is adapted to be mounted for free movement about the spindle 6. Extending outwardly from the plate [3 are arms 20 having formed thereon teeth or threads 2|.

- work 22.

In use the work 22, the pitch diameter of the threads of which is to be determined, is placed between the base 8 and the cap 9 and the spindle moved to bring the head or cap down upon the work to securely hold the work between the base and the head, 8 and 9, respectively. The threads i2 and 2| correspond to the number of threads per inch of the work 22. Consequently, when the work is disposed between the base and cap, 8 and 9, respectively, the threads of such base and cap will snugly fit into the threads of the Then, by observing the markings on the thimble 23 of the micrometer, one can easily determine the pitch diameter of the threads, and the accuracy of their formation.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. An attachment for a micrometer for determining the pitch diameter of the threads of a body comprising a base having a sleeve adapted to receive the anvil of the micrometer and having laterally extended portions provided with threads the number of which correspond to the number of threads per inch on the body to be measured, a cap having a plate provided with an aperture through which the spindle of the micrometer extends and having lateral projections provided with threads corresponding to the threads per inch formed in the work, and means for connecting the head to the spindle for rotation relative thereto.

2. An attachment for a micrometer comprising a cap having a sleeve adapted to receive the anvil of the micrometer and having arm portions extending on opposite corresponding sides thereof with an edge portion of said arm portions provided with screw threads, a cap comprising a plate having a central opening for the projection of the spindle of the micrometer and having arm portions extending laterally therefrom from corresponding side edges of the plate and provided with screw threads in opposed relation to the screw threads on the arm portions of said cap, and means for rotatably connecting said cap to said spindle.

3. An attachment for a micrometer comprising a cap having a sleeve adapted to receive the anvil of the micrometer and having arm portions extending on opposite corresponding sides thereof with an edge portion of said arm portions provided with screw threads, a cap comprising a plate having a central opening for the projection of the spindle of the micrometer and having arm portions extending laterally therefrom from corresponding side edges of the plate and provided with screw threads in opposed relation to the screw threads on the armportions of said cap, and collar elements carried by the spindle on opposite sides of the plate for rotatably connecting the plate to the spindle. I

EMIL J. MARTINEC. 

